Viewing file:  _funcs.py (2.6 KB) -rw-r--r--
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from __future__ import absolute_import, division, print_function
import copy
from ._compat import iteritems
from ._make import Attribute, NOTHING, fields
def asdict(inst, recurse=True, filter=None):
"""
Return the ``attrs`` attribute values of *i* as a dict. Optionally recurse
into other ``attrs``-decorated classes.
:param inst: Instance of a ``attrs``-decorated class.
:param recurse: Recurse into classes that are also ``attrs``-decorated.
:type recurse: bool
:param filter: A callable whose return code deteremines whether an
attribute or element is included (``True``) or dropped (``False``). Is
called with the :class:`attr.Attribute` as the first argument and the
value as the second argument.
:type filer: callable
:rtype: :class:`dict`
"""
attrs = fields(inst.__class__)
rv = {}
for a in attrs:
v = getattr(inst, a.name)
if filter is not None and not filter(a, v):
continue
if recurse is True:
if has(v.__class__):
rv[a.name] = asdict(v, recurse=True, filter=filter)
elif isinstance(v, (tuple, list, set)):
rv[a.name] = [
asdict(i, recurse=True, filter=filter)
if has(i.__class__) else i
for i in v
]
elif isinstance(v, dict):
rv[a.name] = dict((asdict(kk) if has(kk.__class__) else kk,
asdict(vv) if has(vv.__class__) else vv)
for kk, vv in iteritems(v))
else:
rv[a.name] = v
else:
rv[a.name] = v
return rv
def has(cl):
"""
Check whether *cl* is a class with ``attrs`` attributes.
:param cl: Class to introspect.
:type cl: type
:raise TypeError: If *cl* is not a class.
:rtype: :class:`bool`
"""
try:
fields(cl)
except ValueError:
return False
else:
return True
def assoc(inst, **changes):
"""
Copy *inst* and apply *changes*.
:param inst: Instance of a class with ``attrs`` attributes.
:param changes: Keyword changes in the new copy.
:return: A copy of inst with *changes* incorporated.
"""
new = copy.copy(inst)
for k, v in iteritems(changes):
a = getattr(new.__class__, k, NOTHING)
if a is NOTHING or not isinstance(a, Attribute):
raise ValueError(
"{k} is not an attrs attribute on {cl}."
.format(k=k, cl=new.__class__)
)
setattr(new, k, v)
return new
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